I haven't ever really seen this talked about.
Throughout this entire Story, Uchiha Sasuke has gone through multiple different emotions and feelings. At first he was innocent and loving. He loved his family and his brother. He had a good heart and a good soul.
Then the Massacre Happened.
Then his life was warped and changed forever. He dedicated every essence of himself to revenge and murder of his brother. Always seeing visions of his parents slayed right in front of his feet, and he was helpless.
This... Is the true heart of Uchiha Sasuke.
The fact that he was helpless to do anything to SAVE his most important people.
Sasuke met Naruto, and regardless of what he says, he became best friends with Naruto. They saved eachothers lives on different occassions. Team 7 became Sasukes new family.
I know everyone thinks Sasuke left the village to get stronger so that he could get revenge on Itachi. That's not exactly fully true. That was a big part of it.
The real reason however.... Was to get strong enough so that he could defeat Itachi and SAVE Naruto.
Uchiha Sasuke has always been an amazing thinker. He analyzes EVERY situation. He's a Shikamaru/Kakashi type character. He's like a mix. He is very powerful, very smart... But overconfident at times, and underestimates.
Throughout his time with Orochimaru, surely he was plotting and planning an ultimate plan.
Sasuke lost to Naruto in the village. As far as who had the stronger Jutsu anyway. This angered Sasuke, not only because of their rivalry, but for the fact that Naruto would now be looking out for him, instead of the other way around. Sasuke probably felt like Itachi was always stronger, and he wanted to be stronger for once, to be able to protect his teamates and new family, instead of feeling....
Helpless... Which is the main thing i'm trying to explain about Sasuke.
He was reminded by Itachi the pain and agony of the massacre. He made Sasuke relive it. It was for a reason....
Akatsuki was coming for Naruto, and Itachi NEEDED Sasuke to be strong enough with the Mangekyou Sharingan, so that he could control the Ninetails and not let it fall into Akatsukis hands!!! He needed Sasuke to be strong enough to protect Naruto, the Fourths Legacy.
Itachi loved Konoha and wanted peace. He was aware of the power of Sasukes Sharingan, and he viewed Sasuke as a Hero of Konoha. Wanted it to turn out that way anyway.
Sasuke wasn't getting strong enough.
Itachi did what he was there to do, check up on him, and possibly test his strength. He needed Sasuke to get stronger. For the villages sake, and Narutos sake.
Sasuke realized that also.
He did what was necessary in order to get strong... FAST. He cut his bonds with his teamates, cause they would never let him go if he didn't. If he didn't cut his bonds, he would be trapped in the politics of Konoha, doing petty missions while Akatsuki prepared to kidnap and murder HIS BEST friend and teamate.
Sasuke would feel.... Helpless.
And he never wants to feel helpless again. For his TEAMATES sake. For Narutos sake. He knows AKatsuki is coming for Naruto.
So he has three years. He realizes HE MUST go to Orochimaru.
He's went toe to toe with Orochimaru before, a semi serious Orochimaru anyway, but he was a Genin with one tomoe in his Sharingan. When he developed his final tomoe at Vote, he upgraded big time. He was on par with Orochimaru. He probably figured he would get the power he needs as fast as possible, the Kill Orochimaru for the sake of the world and all the prisoners and "What's Right". What a hero would do. Eliminate a Villan. If Sasuke just left that hideout when he was strong enough, leaving Orochimaru alive, he would be responsible for many more lives. He did what a hero would do.
Now the end of his plan.
He was always aware of Itachi, but had a feeling someone else helped him. When he learned of Madara from the Kyuubi, this then was a new ingredient to add onto the grand finale plan. He needed to kill Itachi, but figure out who the other person was, so he could eliminate him also, and whomever else might be capable of hurting Naruto or his team or village.
However, he needed a team.
Nobody is truly strong enough to do anything alone.
That's where Konoha kicks ass.
So he needed to seek out Itachi first.
Along the way, he eliminated perhaps one of Akatsukis strongest... Deidara.
This helped the good guys.
He eliminated Manda as well, a truly evil summon that won't be able to come back and destroy anything.
Itachi didn't want Sasuke to find out anything.
He wanted Sasuke to continue on with his power increasing and save Konoha and Naruto. Itachi wanted Sasuke to take his eyes I believe. Itachi believed in Sasuke.
Sasuke... Didn't take them.
He'll do things his own way.
Finds out about Madara.
Takes in all the info Madara has about the situation and Itachi.
Gets new Targets along the way. Realizing the truth, he wants those responsible for putting Itachi through this hell to pay. However, Sasuke isn't the kind of person who would target anybody who wasn't responsible. He would deal with the elders first, before Madara.
Sasuke then betrays Madara, and doesn't capture the Eight Tails at all, this stalling Akatsukis progress. Causing problems.
Maybe when Sasuke figured out what Biiju they were after, he knew he had some time, since they had to capture the Biiju one after the other. However, he probably didn't plan on Pain being in Konoha RIGHT NOW trying to take Naruto. He needs more time.
So he's currently on his way to Konoha.
He's probably on his way to help Naruto.
No matter what, he doesn't want Naruto to die.
Regardless, maybe he's doing something else.
I still have a weird feeling that everything Sasuke is doing, doesn't just have to do with Revenge for his family... It also has to do with FUTURE PROTECTION of his current loved ones and new important people. He just doesn't wanna feel Helpless ever again.
So he's doing everything in his power. to gain power... At the same time, eliminating very bad people and threats to Konoha. Itachi. Orochimaru. Deidara. All in the end to inevitably SAVE Naruto from the threat of Akatsuki, and save the world from the threat of Uchiha Madara.
Everything will go to plan I'm sure.
Naruto will be saved. Team 7 will be re united.
However... Sasuke won't be able to deal with Madara alone.
He'll need his teamates.
Anyway, your thoughts?
Sorry for length.